drivers/acpi/tables/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils - Table manipulation utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2005, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44
  45 #include <acpi/acpi.h>
  46 #include <acpi/actables.h>
  47
  48
  49 #define _COMPONENT          ACPI_TABLES
  50          ACPI_MODULE_NAME    ("tbutils")
  51
  52 /* Local prototypes */
  53
  54 #ifdef ACPI_OBSOLETE_FUNCTIONS
  55 acpi_status
  56 acpi_tb_handle_to_object (
  57         u16                             table_id,
  58         struct acpi_table_desc          **table_desc);
  59 #endif
  60
  61
  62 /*******************************************************************************
  63  *
  64  * FUNCTION:    acpi_tb_validate_table_header
  65  *
  66  * PARAMETERS:  table_header        - Logical pointer to the table
  67  *
  68  * RETURN:      Status
  69  *
  70  * DESCRIPTION: Check an ACPI table header for validity
  71  *
  72  * NOTE:  Table pointers are validated as follows:
  73  *          1) Table pointer must point to valid physical memory
  74  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
  75  *             name
  76  *          3) Table must be readable for length specified in the header
  77  *          4) Table checksum must be valid (with the exception of the FACS
  78  *              which has no checksum because it contains variable fields)
  79  *
  80  ******************************************************************************/
  81
  82 acpi_status
  83 acpi_tb_validate_table_header (
  84         struct acpi_table_header        *table_header)
  85 {
  86         acpi_name                       signature;
  87
  88
  89         ACPI_FUNCTION_NAME ("tb_validate_table_header");
  90
  91
  92         /* Verify that this is a valid address */
  93
  94         if (!acpi_os_readable (table_header, sizeof (struct acpi_table_header))) {
  95                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
  96                         "Cannot read table header at %p\n", table_header));
  97
  98                 return (AE_BAD_ADDRESS);
  99         }
 100
 101         /* Ensure that the signature is 4 ASCII characters */
 102
 103         ACPI_MOVE_32_TO_32 (&signature, table_header->signature);
 104         if (!acpi_ut_valid_acpi_name (signature)) {
 105                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 106                         "Table signature at %p [%p] has invalid characters\n",
 107                         table_header, &signature));
 108
 109                 ACPI_REPORT_WARNING (("Invalid table signature found: [%4.4s]\n",
 110                         (char *) &signature));
 111
 112                 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
 113                 return (AE_BAD_SIGNATURE);
 114         }
 115
 116         /* Validate the table length */
 117
 118         if (table_header->length < sizeof (struct acpi_table_header)) {
 119                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 120                         "Invalid length in table header %p name %4.4s\n",
 121                         table_header, (char *) &signature));
 122
 123                 ACPI_REPORT_WARNING (("Invalid table header length (0x%X) found\n",
 124                         (u32) table_header->length));
 125
 126                 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
 127                 return (AE_BAD_HEADER);
 128         }
 129
 130         return (AE_OK);
 131 }
 132
 133
 134 /*******************************************************************************
 135  *
 136  * FUNCTION:    acpi_tb_verify_table_checksum
 137  *
 138  * PARAMETERS:  *table_header           - ACPI table to verify
 139  *
 140  * RETURN:      8 bit checksum of table
 141  *
 142  * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
 143  *              table should have a checksum of 0.
 144  *
 145  ******************************************************************************/
 146
 147 acpi_status
 148 acpi_tb_verify_table_checksum (
 149         struct acpi_table_header        *table_header)
 150 {
 151         u8                              checksum;
 152         acpi_status                     status = AE_OK;
 153
 154
 155         ACPI_FUNCTION_TRACE ("tb_verify_table_checksum");
 156
 157
 158         /* Compute the checksum on the table */
 159
 160         checksum = acpi_tb_checksum (table_header, table_header->length);
 161
 162         /* Return the appropriate exception */
 163
 164         if (checksum) {
 165                 ACPI_REPORT_WARNING ((
 166                         "Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)\n",
 167                         table_header->signature, (u32) table_header->checksum,
 168                         (u32) checksum));
 169
 170                 status = AE_BAD_CHECKSUM;
 171         }
 172         return_ACPI_STATUS (status);
 173 }
 174
 175
 176 /*******************************************************************************
 177  *
 178  * FUNCTION:    acpi_tb_checksum
 179  *
 180  * PARAMETERS:  Buffer              - Buffer to checksum
 181  *              Length              - Size of the buffer
 182  *
 183  * RETURN:      8 bit checksum of buffer
 184  *
 185  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
 186  *
 187  ******************************************************************************/
 188
 189 u8
 190 acpi_tb_checksum (
 191         void                            *buffer,
 192         u32                             length)
 193 {
 194         const u8                        *limit;
 195         const u8                        *rover;
 196         u8                              sum = 0;
 197
 198
 199         if (buffer && length) {
 200                 /*  Buffer and Length are valid   */
 201
 202                 limit = (u8 *) buffer + length;
 203
 204                 for (rover = buffer; rover < limit; rover++) {
 205                         sum = (u8) (sum + *rover);
 206                 }
 207         }
 208         return (sum);
 209 }
 210
 211
 212 #ifdef ACPI_OBSOLETE_FUNCTIONS
 213 /*******************************************************************************
 214  *
 215  * FUNCTION:    acpi_tb_handle_to_object
 216  *
 217  * PARAMETERS:  table_id            - Id for which the function is searching
 218  *              table_desc          - Pointer to return the matching table
 219  *                                      descriptor.
 220  *
 221  * RETURN:      Search the tables to find one with a matching table_id and
 222  *              return a pointer to that table descriptor.
 223  *
 224  ******************************************************************************/
 225
 226 acpi_status
 227 acpi_tb_handle_to_object (
 228         u16                             table_id,
 229         struct acpi_table_desc          **return_table_desc)
 230 {
 231         u32                             i;
 232         struct acpi_table_desc          *table_desc;
 233
 234
 235         ACPI_FUNCTION_NAME ("tb_handle_to_object");
 236
 237
 238         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 239                 table_desc = acpi_gbl_table_lists[i].next;
 240                 while (table_desc) {
 241                         if (table_desc->table_id == table_id) {
 242                                 *return_table_desc = table_desc;
 243                                 return (AE_OK);
 244                         }
 245
 246                         table_desc = table_desc->next;
 247                 }
 248         }
 249
 250         ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "table_id=%X does not exist\n", table_id));
 251         return (AE_BAD_PARAMETER);
 252 }
 253 #endif
 254
 255